The present invention relates to an improved method of splicing electrical wires and, in particular, relates to an improved method comprising use of an improved insulating sleeve having a crimp barrel removably retained therein.
In the past, insulated crimp splicers have been comprised of two separate pieces, a ductile metal barrel and a heat-shrinkable insulating sleeve having a bore running therethrough capable of receiving the metal barrel. A splice between two electrical wires was formed by first sliding the sleeve onto one of the wires. The ends of both wires were then stripped and inserted into opposite ends of the metal barrel. The barrel was then compressibly deformed into crimping engagement with the corresponding wires by the application of crimping pressures. The sleeve was slid down the wire and over the barrel. The sleeve was then shrunk down onto the barrel to protect the splice from the environment. Unfortunately, in some cases, because the barrel and the sleeve were separate pieces, one would become lost during storage. Further, in some cases, while forming the splice, the sleeve was inadvertently not put onto one of the wires before crimping the wires into the barrel. In these cases, it was necessary to cut the wires from the barrel and begin again with a new barrel.
Other crimp splicers have been comprised of an insulating sleeve having a metal barrel permanently positioned therein. One prior method of manufacturing this type of crimp splicer involved insertion of the barrel into a heat-shrinkable sleeve in its expanded state and then partially shrinking the sleeve down onto the barrel to permanently retain the barrel therein. Another method of manufacturing this type of crimp splicer involved forceful insertion of a barrel into the bore of the sleeve having a slightly smaller diameter than the diameter of the barrel. A splice between two electrical wires was then formed by stripping the ends of the wires and inserting them into opposite ends of the metal barrel. The barrel was then compressibly deformed into crimping engagement with the corresponding wires by the application of crimping pressures to the sleeve overlying the barrel. The crimping pressures were transmitted directly through the sleeve to the barrel thereby deforming the barrel and permanently retaining the conductors therein. Unfortunately, in response to the crimping pressure, that portion of the wall of the sleeve in the crimped areas was permanently damaged to the extent that residual wall thickness was reduced. In some cases, the damage to the wall caused the tube to split during subsequent heat shrinkage and sealing operations, thereby exposing the underlying conductors. In other cases, the wall thickness was reduced to a point where it was insufficient to provide the necessary physical and dielectric strength.
One prior solution to the problem of damage to the wall caused by crimping involved the reduction of the strength of the crimping forces. Although the reduced crimping forces did not cause damage to the wall of the sleeve, unfortunately, the resultant crimp was, in many cases, unacceptable due to the lower quality of the crimp and crimp connection. Another prior solution to the problem involved shaping the crimping dies so that they would distribute the crimping forces evenly throughout the wall of the tube. Unfortunately, again, the resultant crimp was, in many cases, unacceptable.
Another prior solution to the problem of damage to the wall was disclosed in Martin U.S. Pat. 3,143,595, and involved forming the metal barrel in a substantially hour-glass configuration. The hour glass configuration permitted a cold plastic flow or spread of the sleeve in response to the crimping forces thereby aiding in the prevention of damage to the wall of the sleeve. However, the crimp operation still resulted in some damage to the wall of the sleeve.